US4605546AExpiredUtility

Catalytic process for the production of sulfur from a gas containing H2 S

79
Assignee: ELF AQUITAINEPriority: Jan 31, 1983Filed: Jan 30, 1984Granted: Aug 12, 1986
Est. expiryJan 31, 2003(expired)· nominal 20-yr term from priority
Inventors:Robert Voirin
C01B 17/0456C01B 17/0434
79
PatentIndex Score
21
Cited by
8
References
21
Claims

Abstract

A catalytic process for the production of sulphur from an acid gas containing H2S, in which a part of H2S is catalytically oxidized in order to form an effluent containing H2S and SO2 in a molar ratio of 2:1 and a given quantity of sulphur, then said effluent is contacted with a CLAUS catalyst to form a further quantity of sulphur. The catalytic oxidation of H2S is carried out in the presence of an oxidation catalyst consisting of agglomerates comprising an active alumina thermally stabilized by at least one oxide from the group consisting of SiO2, ZrO2, the rare-earth metal oxides and the alkaline-earth metal oxides to which are associated one or more compounds of metals such as iron that promote the oxidation of H2S.

Claims

exact text as granted — not AI-modified
I claim: 
     
       1. A catalytic process for production of sulphur from a gas, known as an "acid gas", containing H 2  S, in which the acid gas is contacted, at a temperature between 200° and 1000° C. and in the presence of a H 2  S-oxidation catalyst, with a controlled quantity of a gas containing free oxygen in order to form a gaseous effluent containing H 2  S and SO 2  in a H 2  S to SO 2  molar ratio substantially equal to 2:1 as well as sulphur, then said effluent, after cooling, is contacted with a CLAUS catalyst in order to form a further quantity of sulphur, wherein the H 2  S-oxidation catalyst consists of agglomerates having a surface area of at least 5 m 2  /g and comprising an active alumina and either: (a) containing silica as a thermal stabilizer in an amount from 0.5 to 20% by weight of the alumina, to which is associated a compound of iron; or   (b) containing lanthanum oxide and neodymimium oxide as a thermal stabilizer in an amount from 0.5 to 20% by weight of the alumina, to which is associated a compound of iron.   
     
     
       2. A process according to claim 1, wherein the active alumina is thermally stabilized by a quantity of stabilizing oxide or oxides ranging from 1 to 10% by weight of the alumina. 
     
     
       3. A process according to claim 1, wherein the agglomerates of thermally stabilized active alumina have a surface area of at least 40 m 2  /g. 
     
     
       4. A process according to claim 3, wherein said surface area is between 60 and 200 m 2  /g. 
     
     
       5. A process according to claim 1, wherein the overall quantity of the metal compound(s) associated with the agglomerates of thermally stabilized active alumina ranges from 0.5 to 15% of the weight of the calcinated catalyst. 
     
     
       6. A process according to claim 5, wherein said overall quantity ranges from 2 to 12% of the weight of the calcinated catalyst. 
     
     
       7. A process according to claim 1, wherein said iron compound is iron sulphate. 
     
     
       8. A process according to claim 1, wherein the acid gas contains less than 25% H 2  S by volume. 
     
     
       9. A process according to claim 8, wherein the acid gas contains from 0.5 to 20% H 2  S by volume. 
     
     
       10. A process according to claim 1, wherein the acid gas contains less than 25% H 2  S by volume and one or more organic sulphur compounds in an amount of up to about 1% by volume. 
     
     
       11. A process according to claim 10, wherein said organic sulphur compounds are selected from the group consisting of mercaptans, COS and CS 2 . 
     
     
       12. A process according to claim 10, wherein the acid gas contains from 0.5 to 20% H 2  S by volume. 
     
     
       13. A process according to claim 1, wherein the oxidation of H 2  S in the acid gas is achieved at a temperature between 200° C. and 900° C. 
     
     
       14. A process according to claim 1, wherein the oxidation effluent has a H 2  S content lower than 2% by volume, and the contacting of said effluent with the CLAUS catalyst is achieved at a temperature lower than the dew point of sulphur contained in the effluent, said temperature being between 80° C. and 160° C., and the CLAUS catalyst that is loaded with the sulphur that has been formed is periodically regenerated by sweeping with a gas devoid of free oxygen and at a temperature between 200° C. and 400° C. 
     
     
       15. A process according to claim 14, wherein said contacting with the CLAUS catalyst is achieved in a series of catalyst converters, that operate in such a way that at least one of said converters is in the regeneration phase whereas the others are in the CLAUS reaction phase, and the effluent from the oxidation zone is caused to pass, first of all, into the or each converter which is in the regeneration phase, in order to ensure sweeping of the sulphur loaded catalyst contained therein, then after separation of the sulphur, into the or each CLAUS reaction phase converter. 
     
     
       16. A process according to claim 1 wherein the oxidation effluent has a H 2  S content equal to or higher than 2% by volume and the contacting of said effluent with the CLAUS catalyst is carried out at a temperature higher than the dew point of sulphur contained in the effluent through operating in a single catalytic converter or in several of such converters arranged in series. 
     
     
       17. A process according to claim 16, wherein said contacting is carried out at temperatures between 200° C. and 450° C. 
     
     
       18. A process according to claim 16, wherein the contacting of the oxidation effluent with the CLAUS catalyst at a temperature higher than the dew point of sulphur contained in the oxidation effluent is followed by a contacting with a CLAUS catalyst at a temperature below said dew point of sulphur. 
     
     
       19. A process according to claims 14 or 16, wherein the oxidation effluent is contacted with a desoxygenation catalyst before contacting the CLAUS catalyst. 
     
     
       20. A process according to claim 1 or 14 or 16, wherein the gases issuing from the contacting of the oxidation effluent with the CLAUS catalyst are subjected to a thermal or catalytic incineration. 
     
     
       21. A process according to claim 1, wherein lanthanum oxide and neodymium oxide are used for thermally stabilizing the active alumina.

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